body {
    font-family: 'Arial', sans-serif;
    background-color: #f4f4f4;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.container {
    background-color: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    text-align: center;
}

h1 {
    color: #333;
    margin-bottom: 20px;
}

.input-section {
    display: flex;
    margin-bottom: 20px;
}

#todo-input {
    flex-grow: 1;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px 0 0 4px;
    font-size: 16px;
}

#todo-input:focus {
    outline: none;
    border-color: #007bff;
}

#add-todo-btn {
    background-color: #007bff;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 0 4px 4px 0;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.2s ease;
}

#add-todo-btn:hover {
    background-color: #0056b3;
}

#todo-list {
    list-style: none;
    padding: 0;
}

#todo-list li {
    background-color: #f9f9f9;
    border: 1px solid #eee;
    padding: 10px 15px;
    margin-bottom: 10px;
    border-radius: 4px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 16px;
}

#todo-list li span {
    flex-grow: 1;
    text-align: left;
}

#todo-list li.completed span {
    text-decoration: line-through;
    color: #888;
}

.complete-btn, .delete-btn {
    background-color: #28a745;
    color: white;
    border: none;
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
    margin-left: 10px;
    transition: background-color 0.2s ease;
}

.delete-btn {
    background-color: #dc3545;
}

.complete-btn:hover {
    background-color: #218838;
}

.delete-btn:hover {
    background-color: #c82333;
}